These Are The Health Risks That've Got The FDA Worried About 5 Hour Energy

~Twon~/flickrConcerns over the potentially harmful effects of energy drinks, especially when they're combined with alcohol, have been growing in recent years.

A story in the New York Times today (Nov. 15) added to that concern, noting that the Food and Drug Administration (FDA) has received reports of 13 deaths linked to 5-Hour Energy, an energy drink.

The drinks contain about 215 milligrams of caffeine, the equivalent of about two cups of coffee.

Here, a rundown of five worrisome health issues that have been linked to downing stimulating drinks:

Heart problems

In recent years, the company that markets 5-Hour Energy has filed about 30 reports with the FDA of serious injuries associated with its products, including heart attacks, according to the New York Times story.

And in 2007, a 28-year-old Australian man suffered cardiac arrest after consuming eight cans of an energy drink, containing 80 mg of caffeine each, over seven hours. The patient did not have a history of chest pain.

Caffeine and other compounds in energy drinks can boost heart rate and blood pressure, said Dr. John Higgins, associate professor of medicine at the University of Texas Medical School in Houston.

Caffeine can cause heart cells to release calcium, which may affect heartbeat, leading to arrhythmia, Higgins said. The drinks may also disrupt the normal balance of salts in the body, which has been linked to arrhythmia as well.

However, there is not enough evidence to say unequivocally that energy drinks cause heart problems. More research is needed to determine the amount of energy drinks people need to consume in order to experience these negative effects, Higgins said.

The risk of miscarriage

The FDA has also received one report linking a miscarriage to consumption of 5-Hour Energy.

Studies examining the effects of caffeine on miscarriage have been mixed. A 2006 study of more than 1,000 pregnant women found that those who consumed more than 200 mg of caffeine per day (from coffee, tea, soda or hot chocolate) were about twice as likely to have a miscarriage compared with pregnant women who did not drink caffeine. However, a study published in 2008 found no link between caffeine consumption (regardless of the amount) and the risk of miscarriage at 20 weeks of pregnancy.

Because study findings have not been conclusive, the American College of Obstetricians and Gynecologists advises that pregnant women limit caffeine consumption to 200 mg per day.

An increased risk of alcohol injury and dependence

Studies suggest that combining alcohol and energy drinks can be dangerous.

Although caffeine is a stimulant, research suggests it does not "counteract" the sedating effects of alcohol. There is concern that mixing alcohol and energy drinks may keep people awake for a longer period of time, allowing them to consume more alcohol than they ordinarily would, according to an editorial published last year in the Journal of the American Medical Association.

A 2011 study of about 1,100 college students found those who downed energy drinks frequently were about 2.5 times more likely to meet the diagnostic criteria for alcohol dependence than those who did not consume energy drinks. The link may be due to the practice of mixing alcohol and energy drinks, or drinking caffeine to recover from a hangover, according to the JAMA editorial. It could also be that caffeine's effects on the brain play a role in addiction, the editorial says.

Risk of drug abuse

Another study of 1,060 students found that energy drink consumption in the second year of college was associated with an increased risk of prescription drug abuse (use of stimulants or prescription painkillers without a prescription) in the third year of college.

One explanation for the link "is that energy drinks, like prescription drugs … might be regarded by some students as safer, more normative, or more socially acceptable than using illicit 'street' drugs," the researchers wrote in a 2010 issue of the Journal of Addiction Medicine.

Impaired cognition

Although some students rely on energy drinks to pull all-nighters to study for exams, there's some evidence that the excessive levels of caffeine in the drinks impair cognition. A small 2010 study found that drinking moderate amounts of caffeine, about 40 mg, improved performance on a test of reaction time, but drinking higher amounts — equivalent to the levels found in a (250 ml) can of Red Bull, or 80 mg — worsened performance on the reaction test.